1. Field of the Invention
The present invention generally relates to a substrate, in particular, to a substrate for inspecting a thickness of contacts.
2. Description of Related Art
Contacts on substrates of the conventional FCBGA and CSP package adopt the design of copper contacts. After the bonding of the copper contacts and solder balls, a reaction may be produced to cause a tin and copper intermetallic phenomenon which may aggravate due to the time and temperature. As a result, the copper contacts may be consumed, and thus the bonding strength between the contacts and the substrate is reduced to cause a failure of the electronic product at last. Therefore, the thickness of the copper contacts needs to be inspected firstly. A conventional method for inspecting the copper contacts is a destructive inspection method, in which the substrate is sliced for measurement. However, the inspecting time of the destructive inspection method is relatively long, the measurement error is considerably large, and the substrate is destroyed.